<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>模拟数据监测</title>
</head>
<body>
<script type="text/javascript">
    let data = {
        name: "武汉科技大学",
        address: '武汉'
    }
    //无限递归 调用栈炸了 内存溢出
    //错误写法
    // Object.defineProperty(data, 'name', {
    //     get(){
    //         return data.name
    //     },
    //     set(val){
    //         data.name = val;
    //     }
    // })

    //创建一个监视实例对象
    const obs = new Observer(data);

    //准备一个vm实例
    let vm = { };

    vm._data = data = obs;

    //观察者
    function Observer(obj){
        //缺陷：未实现递归(对象嵌套对象就会出现问题)
        const keys = Object.keys(obj);
        //遍历对象当中所有的key
        keys.forEach(key => {
            Object.defineProperty(this, key, {
                get(){
                    return obj[key]
                },
                set(v) {
                  console.log(`${key}的值改变了,变为${v}`);
                  obj[key] = v;
                }
            })
        });
    }



</script>
</body>
</html>
